Systemic antitubercular therapy is clearly indicated for patients with uveitis whose TB test results have recently converted to positive, patients with an abnormal-appearing chest radiograph suggestive of tuberculosis, or persons with positive mycobacterial culture or PCR results to M tuberculosis. Multidrug therapy is recommended because of the increasing incidence of resistance to isoniazid as well as adherence problems associated with long-term therapy. These problems, together with the extremely slow growth rate of TB, contribute to the acquisition of multidrug-resistant tuberculosis (MDRTB). Patients at risk for MDRTB include nonadherent patients receiving single-drug therapy; migrant or indigent populations; immunocompromised patients, including those with HIV infection; and recent immigrants from countries where isoniazid and rifampin are available over the counter.
In brief, treatment entails an initial 2-month induction course of isoniazid, rifampin, pyrazinamide, and ethambutol administered daily, followed by a continuation phase of 4–7 months with 2 drugs. More than 95% of immunocompetent patients may be successfully treated with a full course of therapy, provided they adhere to this regimen. Directly observed therapy plays a crucial role in ensuring this success and is now the standard of care in the treatment of tuberculosis. Treatment protocols have been standardized and are available from the CDC.
More difficult is the treatment approach to patients with uveitis consistent with TB, normal chest radiograph appearance, and positive TB test result. In this situation, a diagnosis of extrapulmonary TB may be entertained and treatment initiated, particularly in cases with medically unresponsive uveitis or other findings supportive of the diagnosis, such as recent exposure to or inadequate treatment of the disease, a large area of induration, or skin test result recently converted to positive. Topical and even systemic corticosteroids may be used in conjunction with antimicrobial therapy to treat the inflammatory component of the disease. Because intensive corticosteroid treatment administered without appropriate coverage with antituberculosis treatment may lead to progressive worsening of ocular disease, any patient suspected of harboring TB should undergo appropriate testing before beginning such therapy.
Patients with a positive TB test result or abnormal chest film appearance for whom systemic corticosteroid treatment is being considered, or patients who have received corticosteroids for longer than 2 weeks at doses greater than 15 mg/day, may benefit from prophylactic treatment with isoniazid for 6 months to 1 year based on infectious disease specialist evaluation. Likewise, patients with latent TB in whom IMT (particularly with tumor necrosis factor inhibitors) is being considered should be treated with isoniazid prophylaxis beginning at least 3 weeks before the first administration.
Agrawal R, Gunasekeran DV, Grant R, et al; Collaborative Ocular Tuberculosis Study (COTS)–1 Study Group. Clinical features and outcomes of patients with tubercular uveitis treated with antitubercular therapy in the Collaborative Ocular Tuberculosis Study (COTS)-1. JAMA Ophthalmol. 2017;135(12):1318–1327.
Nazari Khanamiri H, Rao NA. Serpiginous choroiditis and infectious multifocal serpiginoid choroiditis. Surv Ophthalmol. 2013;58(3):203–232.
Excerpted from BCSC 2020-2021 series: Section 9 - Uveitis and Ocular Inflammation. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.